Final answer:
To calculate cost per unit, divide the total amount spent by the number of units purchased. Precise calculation for $3.04 per unit on January 9th can't be deduced from the provided details which lack specific date and quantity information.
Step-by-step explanation:
The cost per unit for the January 9th transaction appears to be related to an inventory costing method or a similar calculation in a business scenario. To calculate the cost per unit for this particular type of question, we would generally need to divide the total amount spent on the units by the number of units purchased. However, the provided details in the question are insufficient to determine how the $3.04 cost per unit was precisely calculated for January 9th, as there are no transactions explicitly dated January 9th or amounts given for that specific day.
If we were to use the given period prices and amounts spent, we'd calculate the cost per unit for each period by dividing the 'Amount Spent' by the quantity of items. Since the quantities are not provided, we can't perform this calculation accurately. For instance, if the 'Pd 1' amount of $60.00 was spent on 20 units, the cost per unit would be $60.00 divided by 20, equalling $3.00 per unit. This approach is similar to using an index number in inflation tracking, where a base year is used to compare prices over time, but the specific details do not align with calculating a cost per unit for a singular transaction.